Perhaps you should try some spelling variations:
"multiple vaccines research : july 2007" » "multiple access research : july 2007", "multiple crises research : july 2007", "multiple faces research : july 2007", "multiple vaccine research : july 2007", "multiple practices research : july 2007", "multiple accidents research : july 2007", "multiple vaccines research : july 2008", "multiple vaccines research : july 2012", "multiple vaccines research : july 2020"
"bali climate research : july 2013" » "mali climate research : july 2013", "daily climate research : july 2013", "early climate research : july 2013"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"bali climate research : july 2013\") OR (\"multiple vaccines research : july 2007\"))~".
• Removing quotes may allow a broader search: (( bali climate research : july 2013 ) OR ( multiple vaccines research : july 2007 ))~.
• Adding a wildcard symbol may retrieve word variants: (("bali climate research : july 2013") OR ("multiple vaccines research : july 2007"))*.